If Firefox is a bit slow to start up because of all your open tabs, you can turn on a quick setting in Firefox 8 to only load tabs one at a time, when you click on them.

Firefox 8 introduced a few different features, but one that slipped by us was a new BarTab-like feature that stops Firefox from auto-loading tabs. If you have Firefox set to open up your tabs from last time whenever you start it up, you probably notice it takes a while to start up, and can start taking up RAM pretty quickly. To speed it up, just head into Firefox's Options, go to General, and check the "Don't load tabs until selected" box. From then on, it will only load tabs as you click on them, as opposed to loading them all at once on startup. You may have to wait an extra second or two when you do switch to those tabs (since they won't be pre-loaded), but it's a fair trade, depending on how many you usually have open at startup.